Hi! I am very stuck with these problems. I have tried to solve for each of these values, but I keep getting the answers wrong.

Q:
For each of the following strong base solutions determine OH-, H3O+, pH, and pOH:

8.66×10−3 M LiOH

1.15×10−2 M Ba(OH)2

2.2×10−4 M KOH

4.9×10−4 M Ca(OH)2